eating some of her droppings

Every so often I'll see my yellow napped macaw going down to the bottom of her cage and is trying to eat some of her droppings. I clean the metal daily so there isn't very much, if any, clinging to the metal railings.

I also change the paper every day as she goes to the bathroom a lot. She can't reach anything on the paper, but I'm concerned about her eating or scraping off her droppings. Is there a way of stopping her from doing that or is it normal for her?